Linestopping system

ABSTRACT

A linestopping system for pipes includes first and second linestopping means, each linestopping means including an inflatable plug, an inflation means and an insertion means and first and second branch pipe supports each having an apertured flange with a pipe section mounted thereon at an acute angle, each pipe section containing a valve. In use, the pipe supports are disposed on a pipe in spaced apart locations with the pipe sections facing in opposite directions such that upon apertures being cut in the pipe at the pipe supports the inflatable plugs of respective linestopping means are inserted by the insertion means through the apertures in the pipe and subsequently inflated by the inflation means so as to seal off a section of the pipe. Each insertion means includes a plurality of sets of hydraulic clamps, a first set of clamps being fixed relative to the insertion means and a second set of clamps being movable relative to the insertion means, such that the first and second sets are relatively moveable so as to cause insertion of the respective inflatable plug into the pipe. A bypass pipe extends between the first and second linestopping means to allow fluid flow to be maintained when the section of the pipe is sealed off.

DESCRIPTION OF THE INVENTION

The present invention relates to a linestopping system for stopping theflow of fluids or gases in a section of a pipe.

FIELD OF THE INVENTION

Repair and replacement of pipes, whether in an emergency or maintenancesituation, is a financial liability for service providers such asUtilities and Processors. Linestopping presently involves removing anapproximately circular section of approximately the same radius as thepipe from an upper portion of the pipe. Removal of the section canseriously weaken the pipe structure, requiring reinforcement orstrapping of the pipe. This reinforcement may take the form of pipeencasing metal sleeves secured to the pipe. Additionally, concretereinforcing is often used. Considerable human and consumable resourcesare required to ensure adequate reinforcing is provided.

Once the pipe is reinforced, the process of line stopping employedhitherto involves several stages. The first stage is to attach anupwardly protruding branch connection to the pipe, such that thecircumference of the aperture caused by removing the section isenclosed. The support section and the associated line stopper insertionapparatus is then attached to the protruding connection via a flange.The third stage of the operation involves insertion of the linestopperat an angle approximately ninety degrees to the direction of flowthrough the pipe. The linestopper is inserted into the pipe, by way of alinestopper insertion apparatus. Where the line stopper is a rubber linestopper, it is forced through the aperture and deforms to seal aroundthe internal circumference of the pipe. The length of the rubber linestopper is limited to the diameter of the aperture. Alternatively, wherethe line stopper employs a solid hinged rubber seated disc to seal thepipe, the disc is positioned such that the plane of the disc is at anangle approximately ninety degrees to the direction of flow through thepipe. Both these methods have limitations, in addition to the time andcost liabilities previously discussed. These limitations include thephysical size of the equipment, weakening of the pipe to be linestoppedand little or no capability for the equipment to deal with a range ofpipe sizes. Further, these methods are only effective when used withpipes having a smooth interior surface. Any debris or irregularities onthe inside of the pipe greatly reduce the effectiveness of previouslyknown linestopping devices. In addition, these methods result in theapplication of large forces onto the pipeline, which usually causeweakening. Further these methods do not cater for the flow of fluid tocontinue around the section of pipe to be repaired or replaced.

One method for dealing with line stopping, used predominantly in thepetroleum industry, is to insert steel packers with a rubber jacketwithin the pipe. The rubber jacket is arranged such that a seal can beproduced between the pipe and the packer by inflating the rubber jacket.These packers are inflexible and they have to be custom made for eachapplication. They are usually used in very high pressure applications.Other main disadvantages of this method are the requirement to accessone end of the pipe and the interruption of the flow.

SUMMARY OF THE INVENTION

The present invention seeks to, at least in part, overcome some or allof the problems of the prior art outlined above.

According to one aspect of the present invention there is provided alinestopping system for pipes characterised by first and secondlinestopping means, each linestopping means including an inflatableplug, an inflation means and an insertion means, first and second branchpipe supports each having an apertured flange with a pipe sectionmounted thereon at an acute angle, each pipe section containing a valvewherein, in use, the pipe supports are disposed on a pipe in spacedapart locations with the pipe sections facing in opposite directionssuch that upon apertures being cut in the pipe at the pipe supportsinflatable plugs of respective line stopping means may be inserted bythe insertion means through the apertures in the pipe and subsequentlyinflated by the inflation means so as to seal off a section of the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying figures in which:

FIG. 1 represents a schematic side view of a linestopping systemattached to a pipe;

FIG. 2 shows a linestopping plug partially inserted into the pipe inaccordance with the present invention;

FIG. 3 shows the linestopping plug inserted into the pipe and inflatedin accordance with the present invention;

FIG. 4 shows a cross section of the linestopping plug accordance withthe present invention;

FIG. 5 shows a cross section of the insertion device in accordance withthe present invention;

FIG. 6 shows a cross section of the insertion device in a secondposition in accordance with the present invention; and

FIG. 7 shows two linestopping system as shown in FIG. 3 inserted intothe pipe and inflated in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1,2 and 3 there is shown a linestopping system 10. Thelinestopping system 10 includes a branch pipe support 20, an insertionapparatus 30, a linestopping plug 50, an insertion push rod 70 and apumping means 90.

The linestopping system 10 may be attached to a pipe 12 for the stoppingof the flow of a fluid in a pipe 12 such as a water supply pipe.

The branch pipe support 20 includes a curved apertured flange panel 22substantially the same or slightly larger in diameter than the outsidediameter of the pipe 12 to which it is to be attached. The branch pipesupport 20 also includes a pipe section 24 which is attached to theflange panel 22 at a first end and has a reinforced connection flange 26at a second end. The connection flange 26 includes a valve 28 whichallows the branch support pipe 20 to be sealed off so as to preventfluid loss from the pipe 12. The connection flange 26 may includeapertures for attachment means such as nuts and bolts to enable theinsertion apparatus 30 to be securely and releasably attached. The pipesection 24 is joined to the flange panel 22 such that the centre line ofthe pipe section 24 forms an angle of between 30 and 50 degrees,preferably between 35 and 45 degrees, for example, about 40 degrees tothe flange panel 24.

Once the flange panel 22 is mounted to the pipe 12, an aperture is cutin the pipe 12 by any convenient cutter means member in the pipe section24.

The insertion apparatus 30 includes an insertion pipe 32, an insertionmechanism 34 and a number of bypass pipe connectors 36.

The insertion pipe 32 has a lower end 38 and an upper end 40, the lowerend 38 includes a connection flange 42 and at least one bypass pipeconnectors 36. The upper end 40 of the insertion pipe 32 includes aconnection flange 43. The upper end of the insertion pipe 32 alsoincludes a number of valves 33 as seen in FIGS. 5 and 6. The valves 33may be used to release air from the insertion pipe 32 when the valve 28is opened. The connection flange 42 attaches to the connection flange 26in use, thus joining the insertion apparatus 30 to the branch pipesupport 20.

The insertion mechanism 34 is attached to the upper end 40 of theinsertion pipe 32 at the connection flange 43. The insertion mechanism34 holds and inserts the push rod 70 during the insertion of the plug 50into the pipe 12. The insertion mechanism 34 is described in more detailbelow.

The push rod 70 is attached to the plug 50. The push rod 70 includes ahollow tube 72 which the clamping means 44 and 46 grip and push into thepipe 12 using the jacking means 48. The plug 50 may also be withdrawnusing the push rod 70.

The tube 72 is hollow, and may be between 3 and 7 metres long such as 4to 6 metres long, and includes a set of attachments 73 at the upper endfor pressurised fluid to be fed into the tube 72. A hose 74 also runsdown the middle of the tube 72 to feed pressurised fluid to the plug 50.Further, the tube 72 incorporates attachments at its lower end so thatpressurised fluid may be fed into the upper end attachment 73 through tothe lower end of the tube 72 and then fed into the plug 50 as seen inFIGS. 5 and 6.

The pressurised fluid is supplied by a fluid supplying means 90. Thefluid supplying means 90 supplies fluid at two pressure levels. Thelower pressure level fluid is fed into the tube 72 by hose 92 throughattachment 73 for use in inflating the plug 50. The higher pressurefluid is fed along hose 94 and into a hose 74 in the tube 72 throughanother attachment 73 as seen in FIG. 1 and 2.

In FIG. 4 there is shown a plug SO. The plug 50 includes a nose cone 52a balloon 54 and a base plug 56. The balloon 54 is sealingly attached tothe nose cone 52 and the base plug 56 such that the balloon 54 mayexpand to a diameter of up to 3 times the diameter of the nose cone 52and the base plug 56, as can be seen in FIG. 3.

The nose cone 52 includes a plurality of apertures 58. The apertures 58are located on the side of the nose cone 52 which is lowermost when thenose cone is inserted into the pipe 12. Each aperture 58 is connected toan inlet pipe 60. The inlet pipes 60 join together and connect to asingle jet hose 62. The jet hose 62 runs through the length of the plug50 to the interior of base plug 56. The jet hose 62 is sealinglyconnected to the base plug 56 and the jet hose 62 exits the base plug 56and connects to the base of the tube 72 of the push rod 70. The jet hose62 enters the base of the tube 72 and connects to the hose 74 whichcontinues up the inside of the tube 72 until it reaches the end where itexits the tube 72 and connects to a fluid supplying means 90 as seen inFIG. 1 and 5.

The plug 50 is inflated by a fluid, typically water, being pumped intoan interior cavity 64 of the plug 50 by the fluid supplying means 90.The pressure of the fluid causes the plug 50 to inflate and increase indiameter. The fluid is fed into the cavity 64 of the plug 50 from aninflation pipe 66. The inflation pipe 66 feeds the pressurised fluidfrom the interior of the tube 72 into a connection 68 in the base plug56.

The balloon 54 is constructed from an outer cover of flexible softmaterial 80, such as rubber, and an interior of resilient strands 82woven around the interior of the material 80. The material 80 is between20 and 60 mm, for example, 40 mm thick.

The plug 50 is designed to fit snugly inside the insertion pipe 32. Theconstruction of the balloon 54 allows the balloon 54 to expand, such asup to three times the original diameter, while having the properties ofa soft deformable outer skin and a firm inner core which can withstandinternal pressures sufficient to inflate the balloon 54 in the interiorof a pipe 12 in which pressurised fluid is flowing.

The base plug 56 incorporates an attachment means 84 which allows thepush rod 70 to be connected to the plug 50. The attachment means forms ajoint 86 which allows the plug 50 to be hingedly attached to the pushrod 70 allowing the plug 50 to align itself and be substantially inlongitudinal alignment with the pipe 12 as can be seen in FIG. 1,2 and3.

FIGS. 5 and 6 shows a cross section of the insertion device 34 attachedto the insertion pipe 32, the push rod 72 and the base plug 56 of theplug 50. The insertion device 34 includes an insertion support 35. Thefirst clamping means 44, second clamping means 46 and jacking means 48are attached to the insertion support 35.

The first clamping means 44 and the second clamping means 46 eachinclude a set of hydraulic clamps 45. Each hydraulic clamp 45 includes agripping surface 47.

The first clamping means 44 are fixedly attached to a recess in theinsertion support 35. The second clamping means 46 are fixedly attachedto the jacking means 48. The jacking means 48 moves the second clampingmeans 46 between a first position shown in FIG. 5 and a second positionshown in FIG. 6.

The insertion device 34 may include a sealing mechanism to stop anyleakage of fluid from around the tube 72.

To move the push rod 70 into the pipe 12, the following sequence ofoperation is performed.

The first clamping means 44 engages and holds the tube 72 of push rod 70in position while the jacking means 48 moves the second clamping means46 to the second position as seen in FIG. 6. The second clamping means46 then engage the tube 72 holding it immovably with respect to thesecond clamping means 46. The first clamping means 44 is then disengagedfrom the tube 72. The jacking means 48 then moves the second clampingmeans 46 and therefore the tube 72 towards the first clamping means 44,to the first position as shown in FIG. 5.

This operation is repeated to move the push rod 70 and thus the plug 50into the pipe 12. By reversing the aforementioned procedure the push rod70 and plug 50 may be withdrawn from the pipe 12 back into the insertionpipe 32. This operation is known as `Hand over Hand` and allows theinsertion apparatus 34 to insert the plug 50 into a live or pressurisedpipe 12 in which there may be fluid flowing under a considerablepressure. The clamping means 44 and 46 allows the tube 72 and plug 50 tobe firmly and securely located with respect to the aperture in the pipe12. The hand over hand method provides a secure grip and allows the plug50 to be removed from the pipe 12 even as flow in the pipe 12 appliespressure in the upstream side 14 of the pipe 12.

In FIG. 7 there is shown two linestopping systems 10a and 10b used toblock off a section of a pipe 12 that has been damaged. The plugs 50,when inserted allow a damaged section 100 of the pipe 12 to be isolated.The flow of fluid in the pipe is able to be maintained by diverting thefluid out of the linestopping system 10a on the upstream side of thedamaged section 100 through bypass pipe connector 36 into bypass pipe102. To maintain an adequate flow of fluid through the bypass pipe 102 apump 104 can be situated along the pipe 102.

The preferred embodiment and an example of use is described as follows.

In use, to stop the flow of fluid in a pipe 12 the following procedureis employed. The branch support pipe 20 is welded or otherwisepermanently attached to a section of a pipe 12 in an upstream position14 of a section of the pipe 12 to which flow is to be stopped. Thebranch support pipe 20 is situated in a position at the top of the pipe12, that is if the pipe is looked at in cross section the centre line ofthe pipe 24 would be in a substantially twelve o'clock position.

The branch support pipe 20 has a pipe section 24 which is at an angle ofbetween 30 and 50 degrees, for example 40 degrees to the angle of thecentre line of the pipe 12. The angle of 40 degrees provides the plug 50with an angle of entry that allows the nose cone 52 to slide across thebottom the pipe 12 at a reduced friction force than if the angle washigher. Further the entrance angle of 40 degrees from the centreline ofthe pipe 12 reduces the overall height of the linestopping system 10when in use.

A cutting device in a substantially watertight housing may be sealinglyattached to the branch support pipe 20 and the valve 28 is opened. Thecutting device enters the branch support pipe 20 and cuts a section ofthe pipe 12 out. The valve 28 is then sealed and the housing and cuttingdevice are removed. The valve 28 may be in the form of a sluice gate.

The insertion apparatus 30 is then releasably and sealingly attached tothe branch pipe 20. The insertion apparatus 30 has the plug 50 attachedto the push rod 70 situated snugly inside the pipe a s can be se en inFIG. 1. The valve 28 is then opened and the insertion apparatus 30 isused to move the push rod 70 toward the pipe 12, which thereby causesthe plug 50 to be inserted into the pipe 12 as can be seen in FIG. 2.When the plug 50 is inserted into the pipe 12 it is then inflated asseen in FIG. 3. The inflation of the plug 50 causes the flow in the pipe12 to stop.

To keep the fluid flowing in a pipe 12, linestopping systems 10a and 10bmay be employed at an upstream and downstream position of, for example,a break in the pipe 12, as can be seen from FIG. 7. Once thelinestopping systems 10a and 10b are in position the flow in the bypasspipe connectors 36 may be started by opening the valves 37. The fluid inthe pipe 12 may then flow through bypass pipe 102 without interruptionaround the section of pipe 12 to be isolated. The flow of the fluid inthe bypass pipe 102 may be increased by using a pump 104 as seen in FIG.7.

In many older pipes there can be considerable debris on the floor of thepipe 12. This debris can reduce the effectiveness of the linestoppingoperation and make it difficult for the plug 50 to be inserted into thepipe 12. To alleviate this problem the following method may be employed.

The high pressure fluid from the fluid supplying means 90 may be fedfrom the hose 94 into the hose 74 and then into jet hose 62 and throughto the apertures 58 where it is expelled to push debris out of the way.The insertion angle of the plug 50 causes the nose plug 52 to push someof the debris out of the way, and the high pressure fluid from the jethose 62 assists in the removal of any debris left over. The plug 50 maybe inserted more than once to push and squirt clear a large enoughsection of pipe for an effective linestopping operation.

The plug 50 of the linestopping system 10 includes a thick outercovering of rubber. The plug 50 may be approximately 400 mm in outerdiameter when uninflated for use with a pipe 12 of approximately 1000 mminner bore. The plug 50 for this type of pipe 12 would be approximately3.5 m long when uninflated. The length of plug 50 and the deformablerubber outer cover allow the plug 50, when uninflated in the pipe 12, toseal around debris and irregularities of up to 100 mm in size.

When the section of pipe to be replaced or repaired has been attendedto, the linestopping plug or plugs 50 may be deflated and withdrawn fromthe pipe. The deflated plugs 50 are withdrawn into the pipe by theinsertion mechanism 34. The valve 28 is then closed and the insertionmechanism 34 can be detached from the branch pipe support 20. The branchpipe support 20 is left in position on the pipe 12 permanently.

The linestopping system 10 may be used with a large variety of pipediameters and with very high internal pressures, for example up to 1100kpa.

The length of the plug 50 allows for a larger surface area than otherknown linestopping devices. The larger surface area of the plug 50results in a lower pressure being required to effectively stop the flowin the pipe 12. This is very important in frail and old pipes as toohigh on internal pressure may rupture or further damage the pipe.

Modifications and variations such as would be apparent to the skilledaddressee are deemed to be within the scope of the present invention.

I claim:
 1. A line stopping system for water supply pipes characterizedby first and second line stopping means, each line stopping meansincluding an elongated inflatable plug, an inflation means and aninsertion means, first and second branch pipe supports each having anapertured flange with a pipe section mounted thereon at an acute angle,each pipe section containing a valve wherein, in use, the pipe supportsare disposed on a pipe in spaced apart locations with the pipe sectionsfacing in opposite directions such that upon apertures being cut in thepipe at the pipe supports inflatable plugs of respective line stoppingmeans may be inserted by the insertion means through the apertures inthe pipe and subsequently inflated by the inflation means so as to sealoff a section of the pipe, wherein each inflatable plug includes a noseportion and a base portion and an annular inflatable balloon portionsealingly attached to the nose portion and the base portion, the noseportion, the base portion and the balloon portion defining a hollowportion of the inflatable plug, the base portion being connected to theinsertion means, the nose portion leading into the pipe upon insertionand the base portion trailing into the pipe upon insertion, and theballoon portion being sufficiently flexible when uninflated so as tobend when the inflatable plug contacts an interior wall of a watersupply pipe upon introduction by the insertion means so as to facilitateinsertion and also being arranged to be inflated to a larger diameterthan the nose portion or the base portion, the balloon portion of eachinflatable plug including a soft deformable outer skin and a firm innercore which can withstand internal pressures, the outer skin beingarranged, when the balloon is inflated, to engage around its entireperiphery with the interior wall of the pipe with the outer skin and theinner core being disposed at the periphery of the hollow portion.
 2. Aline stopping system according to claim 1, characterized in that thehollow portion extends longitudinally from the nose portion to the baseportion and laterally across the entire width of the inflatable plugwithin the balloon portion.
 3. A line stopping system according to claim1, characterized in that the firm inner core is formed of resilientstrands woven around the interior of the soft deformable outer skin. 4.A line stopping system according to claim 3, characterized in that theouter skin is from 20 mm to 60 mm thick.
 5. A line stopping systemaccording to claim 1, characterized in that a respective relatively lowpressure conduit extends from the inflation means to each inflatableplug through the respective base portion thereof, and each inflatableplug is provided with a high pressure nozzle in the nose portionthereof, for expelling a high pressure jet of fluid into the pipe forclearing away debris at the bottom of the pipe, the nozzle beingconnected by a relatively high pressure fluid conduit through the baseportion to a supply of fluid.
 6. A line stopping system according toclaim 5, characterized in that each high pressure fluid conduit iscontained within a low pressure fluid conduit over a major portion ofits length.
 7. A line stopping system according to claim 1,characterized in that the acute angle of the pipe sections is from 30°to 50° to the center line of the pipe.
 8. A line stopping systemaccording to claim 7, characterized in that the acute angle of the pipesections is from 35° to 45° to the center line of the pipe.
 9. A linestopping system according to claim 1, characterized in that there isprovided a bypass pipe which is arranged to extend between the first andsecond line stopping means to allow fluid flow to be maintained when thesection of the pipe is sealed off.
 10. A line stopping system accordingto claim 9, characterized in that the bypass pipe contains a pump forenhancing fluid flow along the bypass pipe.
 11. A line stopping systemaccording to claim 1, characterized in that each insertion meansincludes a plurality of sets of hydraulic clamps, a first set of clampsbeing fixed relative to the insertion means and a second set of clampsbeing movable relative to the insertion means, such that the first andsecond sets are relatively movable so as to cause insertion of therespective inflatable plug into the pipe.